Delhi-based NGO Centre for Science and Environment (CSE) has said that vehicles, including those running on diesel, emit the deadliest toxins.
Noting that cars emit more Particulate Matter (PM) 2.5 than several other key pollution sources in Delhi, the CSE said the auto industry is underplaying the toxic and cancer-causing effects of diesel emissions.
The CSE said that estimates of the International Council on Clean Transportation say that cancer risk from diesel vehicles in Delhi is four times higher than petrol cars.
CSE Director General Sunita Narain said an IIT Kanpur study has established that diesel cars on an average contribute 78 per cent of PM 2.5 from four wheelers.
"This is significantly higher than the contribution of petrol and CNG cars. Cancer effect occurs at very small doses. According to California Air Resources Board the number of excess cancer cases per million people due to lifetime exposure to only 1 microgramme per cum of diesel particulate is 300 as against 29 for benzene that comes predominantly from petrol.
"The cancer potency of diesel particulate matter is 10 times more than benzene. Even after improving emission standards in California cancer risk from diesel particulate matter in Los Angeles is 68 per cent," the CSE said.
The CSE said estimates of International Council on Clean Transportation on cancer risk from diesel vehicles in Delhi are four times higher than petrol cars.
"More than 2,80,000 avoidable cancer deaths in Delhi are being attributed to diesel exhausts. Particulate emissions from diesel and coal combustion are more harmful than others," she said.
She said that cars emit more PM 2.5 than several other key pollution sources in Delhi while they also emit more Nitrogen oxides (NOx), which are are a family of poisonous, highly reactive gases, than several other key pollution sources in Delhi.
The green body said that the action taken by the government to curb air pollution has been showing results and warned that it cannot be "derailed".
"CSE condemns the misleading number game and motivated campaign of the auto industry to claim that vehicles in Delhi are an insignificant source of pollution. It is ironical that now when action has started to show results to curb the killer air pollution in the city detractors are out to derail the process," the body said.
"Instead of ensuring that the action builds up momentum quickly, motivated campaigns have been launched to subvert the process. While action on all key sources should be stepped up, vehicles including diesel vehicles will require stringent action as they emit the deadliest toxins within our breathing zone," the CSE said.